The phenoloxidases of the ascomycete Podospora anserina

Prillinger, Hansjörg; Esser, Karl

doi:10.1007/bf00267190

Cited by 66 publications

(14 citation statements)

References 34 publications

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“…The initial molecular characterization suggested that grisea codes for a copperdependent transcription activator (15). This finding is in good agreement with the observed pleiotropic effects displayed by the long-lived mutant that was selected after chemical mutagenesis (25). We show that this mutant is a loss-of-function mutant in which the expression of grisea is defective.…”

supporting

confidence: 85%

Mitochondrial DNA rearrangements of Podospora anserina are under the control of the nuclear gene grisea

Borghouts

Kimpel²,

Osiewacz³

1997

Proc. Natl. Acad. Sci. U.S.A.

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Podospora anserina is a filamentous fungus with a limited life span. Life span is controlled by nuclear and extranuclear genetic traits. Herein we report the nature of four alterations in the nuclear gene grisea that lead to an altered morphology, a defect in the formation of female gametangia, and an increased life span. Three sequence changes are located in the 5 upstream region of the grisea ORF. One mutation is a G 3 A transition at the 5 splice site of the single intron of the gene, leading to a RNA splicing defect. This loss-of-function affects the amplification of the first intron of the mitochondrial cytochrome c oxidase subunit I gene (COI) and the specific mitochondrial DNA rearrangements that occur during senescence of wild-type strains. Our results indicate that the nuclear gene grisea is part of a molecular machinery involved in the control of mitochondrial DNA reorganizations. These DNA instabilities accelerate but are not a prerequisite for the aging of P. anserina cultures.Aging of biological systems, as the progressive functional impairment of living beings leading to an increase in agerelated mortality, is a complex process that is dependent on both environmental and genetic factors. With regard to the genetic basis, instabilities of the mitochondrial DNA (mtDNA) were reported in various organisms to be involved in aging leading to mitochondrial dysfunction and degeneration (for reviews, see refs. 1 and 2). Moreover, increased instabilities of the mtDNA were found to lead to premature degeneration processes. Examples of this type are premature death syndromes in fungi and various neuromuscular diseases in humans (for reviews, see refs. 3-5). Interestingly, in some cases, these syndromes are due to the mutation of a nuclear gene that demonstrate that the integrity of the mtDNA is under the control of nuclear factors (6-10). Unfortunately, until now, the molecular mechanisms involved in this maintenance function have not been elucidated in any case.In the filamentous fungus Podospora anserina, all wildstrains are characterized by a limited life span. After prolonged vegetative growth, they display various symptoms of senescence. Since the first description of this syndrome (11), it has become clear that nuclear-mitochondrial interactions are crucially involved in its control (for reviews, see refs. 12-15). Detailed molecular investigations revealed that gross reorganizations of the mtDNA occur during senescence. These reorganizations are almost quantitative and lead to impairment of the energy-generating system located in mitochondria. Similar processes were subsequently reported to occur in senescing strains of Neurospora (16)(17)(18). In all cases, the activity of mobile genetic elements of circular or linear structure were found to be relevant. More specifically, in P. anserina, it appears that the mobility of a circular plasmid, termed plasmid-like DNA (plDNA) or ␣senDNA (19,20), which is a derivative of the first intron of the cytochrome oxidase gene subunit I (COI), is responsible f...

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supporting

confidence: 85%

Mitochondrial DNA rearrangements of Podospora anserina are under the control of the nuclear gene grisea

Borghouts

Kimpel²,

Osiewacz³

1997

Proc. Natl. Acad. Sci. U.S.A.

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“…The mutant is characterized by an increase in lifespan of about 60%, a reduced growth rate and by female sterility, and displays an altered morphology (e.g., formation of gray instead of black ascospores) (Prillinger and Esser 1977;Tudzynski and Esser 1979). Interestingly, Grisea codes for a protein with signi®cant sequence identity to the Zn(II) module at the N-terminus of the various yeast transcription factors introduced above (Osiewacz and Nuber 1996).…”

Section: Introductionmentioning

confidence: 98%

GRISEA, a copper-modulated transcription factor from Podospora anserina involved in senescence and morphogenesis, is an ortholog of MAC1 in Saccharomyces cerevisiae

Borghouts

Osiewacz²

1998

Mol Gen Genet

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The initial characterization of Grisea suggested that this gene codes for a transcription factor involved in the genetic control of cellular copper homeostasis in Podospora anserina. Here we demonstrate that GRISEA activates in vivo gene expression in Saccharomyces cerevisiae and is characterized by a modular organization. The DNA-binding domain was mapped to the first 168 N-terminal amino acids and the transactivation domain to the C-terminal half of the protein. Increased levels of copper in the growth medium lead to repression of the transactivation function possibly via intramolecular interactions between parts of the DNA-binding domain and the transactivation domain. The wild-type copy of Grisea was found to complement the phenotype of the mac1-1 mutant of S. cerevisiae. GRISEA is able to bind to the promoter of CTR1, a MAC1 target gene that encodes a high-affinity copper transporter. Taken together, the data reported here and in earlier investigations indicate that GRISEA is an ortholog of the yeast transcription factor MAC1 and suggest at least a partial conservation of the molecular machinery involved in the control of cellular copper homeostasis in eukaryotes. Remarkably, in P. anserina, the spectrum of phenotypes affected by this regulatory protein is much broader than that known in yeast and includes morphogenetic traits as well as lifespan and senescence.

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“…The presence of isozymes of tyrosinase in basidiomycetes was reported in Agaricus bisporus (23,24) and Schizophyllum commune (25). Three isozymes of polyphenoloxidase with different substrate specificities were shown to be under polygenic control in Podospora anserina (26). The presence of inhibitors for tyrosinase in mycelial extracts was shown in C. macrorhizus.…”

Section: Discussionmentioning

confidence: 96%

Effect of 2-deoxy-D-glucose on the induction of tyrosinase in Coprinus macrorhizus.

Nyunoya

Ishikawa

1980

J. Gen. Appl. Microbiol.

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The phenoloxidases of the ascomycete Podospora anserina

Cited by 66 publications

References 34 publications

Mitochondrial DNA rearrangements of Podospora anserina are under the control of the nuclear gene grisea

Mitochondrial DNA rearrangements of Podospora anserina are under the control of the nuclear gene grisea

GRISEA, a copper-modulated transcription factor from Podospora anserina involved in senescence and morphogenesis, is an ortholog of MAC1 in Saccharomyces cerevisiae

Effect of 2-deoxy-D-glucose on the induction of tyrosinase in Coprinus macrorhizus.

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